DD-1 Lack Of Signal Question

[Joe50302]

I have a quick question about using the DD-1 I purchased a week ago and was hoping someone might be able to shed a little light on it.

I read the manual and watched some YouTube videos of Steve Meade using it to get familiar with it. I used the unit on both my truck system as well as my brothers. Both vehicles now sound better after using the DD-1 and I am extremely happy having purchased it.

My friend just installed a new stereo system in his boat and wanted to adjust his radio/amp using the DD-1 because he heard the results of both mine and my brothers systems. I had to download the test tones from D'Amore's website however since his radio doesn't have a CD player. Not sure if this has any bearing on my issue.

Here is the situation at hand. When I started to make to the head unit, I noticed I wasn't getting any signal to the DD-1. The "Power" light was illuminated, but we were able to max out the radio volume without any of the other lights coming on. No "Signal" light, neither the 40Hz or 1kHz light, nor the "Distortion" light. If we plugged the amp back in, you could hear the test tones playing through the stereo plain as day. I could never get the DD-1 to perform the way it did when we adjusted the other two vehicles. I even went so far as to double check my system again just to make sure the unit was still working correctly, and it was.

Any ideas on what might be causing this issue? The radio on the boat is a JBL PRV-175 if that makes any difference. I don't see why it would since it is a normal 12 volt radio.

Thanks in advance to anyone that might be able to point me in the right direction on this.

[audiofanaticz]

Im assuming your trying to tune it thought the RCA cables.

Make sure that any sort of crossover setting on the radio is turned off!

If there is a high pass filter setting turn on and its set for 80hz, and your trying to use a 40hz track, that 40hz track will be very weak, and most likely not register on the dd-1

Sometimes if you are using the left channel of the radio rca output and you get no signal then try using the right channel rca, or vice versa.

Try hooking the amp back up to the radio, unhook the speakers from the amp, and turn the gain all the way down on the amp.

Hook the dd-1 up to the amp as if you are tuning the amp, but use a 0db track and use it for the maximum radio volume setting.

Once you found that, start turning up the gain on the amp at your desired track such as -5 or -10 db and set your amplifier gain.

[Joe50302]

Correct, I was trying to find the max volume on the head unit before I moved on to the amp gains.

Everything on the head unit was zeroed out. Bass and treble set to zero, loudness turned off, etc.

Trying both RCA's is something I didn't do. I will check that out ASAP. I will also try finding the max head unit volume through the amp like you suggested.

Thanks for the suggestions. I really appreciate it. Will let you know the results as soon as I get them.

[audiofanaticz]

I believe there are instructions on how to find the max volume of the head unit through the amp on the next page or two in the manual if my instructions are not clear enough.

I think the main issue you are running into is with the radio preout voltages.

JVC says it is 2 volts, but how they get 2volts is not how others get 2 volts.

Each rca pre output is 1 volt, so you have 1 volt for your left channel and 1 volt for your right channel. Add them together and you have 2 volts..

This seems to be how some companies are advertising the pro output voltage now days it seems (not all but some).

While other companies that advertise 2volts would have 2 volts at the left output and 2 volts at the right output. Sure you could total that up for a 4volt output, but realistically its a 2volt output.

How JVC maybe doing it is to make it sound like the radio is better than it actually is.

If it said 1volt rca pre outputs people may over look it and not buy it due to that fact, so they add the 2 ouputs together and say its 2 volts.

Marketing.....

So anyways now that I said that, the dd-1 will only work on a radio with 1.2volts of output power or more.

If the JVC is only putting out 1volt of output per rca that would explain why you cant get a signal to pop up, its not enough to trigger the dd-1.

So finding the max radio volume through the amplifier should work, with the gain all the way down that output voltage should be amplified enough to trigger the dd-1 signal light.

[mothra]

just me personally, i have had varying results going directly to the RCA. on my one of my personal vehicle I have a Pioneer 720BT. Through the RCAs by the amp it would say 1k distortion at 56 and 40hz distortion at 52. then plugged into the amp with connection at the amp speaker terminal, distortion at 61 on both 1kHz and 40hz. while this isn't something that happens all the time, I've just gotten to the point that I only connect via speaker level at the amp or deck.

[audiofanaticz]

That is mostly due to the different frequencies being played and why you use a 1khz tone for mids and highs and a 40hz tone for low.
If it is a 4channel amp and you want to set it accurate as possible I think the instructions say something about playing both tracks and then using the lower of the 2 for the max headunit volume or something like that.

Also it is very frequent that you will see a difference in max volume between your sub output and your front/rear outputs.

Same goes for the headunit amplifier if your using that, and the rca preouts.

[mothra]

i wasn't pointing out the difference in volume level, I was pointing out that I've had distortion at different volumes when taken at speaker level at the amp and RCA on the same exact vehicle. not saying it's broken, just giving the OP a perspective to possible try at speaker level instead of RCA.

Edited July 20, 2016 by fasfocus00

[Joe50302]

I haven't had a chance to go back over to my friend's house and give his boat system a second go-round with the new info that audiofanaticz gave me yet, but that will be happening tonight after work, and I will post here on the results.

When I used the DD-1 on my system this past weekend, it showed distortion at exactly the same head unit volume when I tested it through the radio RCA's and the amp speaker outputs. Testing both the 40Hz and 1kHz tones. My brother's system was the same too.